Asiel Leal Celdeiro

Software Engineer

  Europe (GMT+2)



Hi there! My name is Asiel.

I'm a Software Engineer with extensive professional experience in the Software Development Industry and full time developer and learner.

That's exactly why I created this site at the end of 2023. I did it with the hope I could share enough knowledge here so other developers can learn easily many of the things I had to learn the hard way. My passion for helping others made me post +300 answers in StackOverflow but that setup was not working for me anymore, hence this site came alive ;)

As a nice side effect, it's helping me dive deeper in the knowledge I use in my everyday work. In fact, many of the articles I've written here are kind of a memo for myself for many of the things I learn and want to keep at hand for when I need them again.

In my free time I usually play chess , read books (and take some notes ) , write articles on this site, or I'm with my wife and son having some fun. I enjoy watching a good movie or traveling and taking some nice pictures .

If you reach out through the contact options on this page, I'll be ready to answer any question you may have about Java, SQL, Spring Boot, JUnit, Mockito, Hibernate, Maven, Gradle, Git, TDD, OOP, Design Patterns, REST, BDD and probably more. But, hey, the tech landscape is constantly evolving; if I don't know the answer we both can investigate together —that's the fun of it —

And, of course, you can access my Resume from this link I'm leaving here.

Important dates in my professional career
  • lealceldeiro.com

    July 2024

    I decided to start my path as a Freelance Software Engineer under the brand of lealceldeiro.com.
    With extensive experience in software development and a background in computer science, I can bring a huge wealth of knowledge into any project I work on.

    1 Project Sports | Notch

    Java Spring Boot PostgreSQL Liquibase Hibernate Mockito JUnit Docker Maven Gradle Git Bitbucket AWS Checkstyle Testcontainers Stripe API

  • eDreams ODIGEO

    March 2024

    After being in the industry for more than 9 years, I joined eDreams ODIGEO as a Java Software Engineer to help their teams of travel enthusiasts shape the future of the online travel agencies and help their customers get the most out of their money when planning their next trip.

    1 Project E-Commerce

    Java RESTEasy Google Guice JBoss GCP Hibernate Kafka Cucumber Mockito JUnit Oracle Docker Maven K8s Jenkins Git Datadog

  • UncommonPurpose

    August 2022

    We humans are difficult to satisfy — I'm no exception. In 2022, my frustration for not feeling I was "contributing to something meaningful (project/product-wise)" was fueled by an offer I received from a Startup based in Vancouver to work on a brand-new product they were developing. I talked to the product founders, underwent several interviews, and met the team.

    That's when I decided I'd join UncommonPurpose in this new adventure. I resigned from my previous position, and after the notice period finished, I started to work remotely with the Notimo team.

    Continuing with my focus on backend development, here, my main duties were designing, reviewing, developing, testing, and maintaining product features as a Backend Java Developer. Additionally, on a daily basis, I collaborated with the Director of Engineering, Product Owner, and the rest of the team in defining roadmaps and requirements, planning releases, and participating in other scrum-related activities.

    Ultimately, the company decided to wind down the project. It was a difficult moment for the whole team, which had invested an enormous amount of energy and effort into making the user experience the best possible.

    1 Project Professional Services

    Java Spring Boot Thymeleaf Oauth OpenAPI PostgreSQL Liquibase Hibernate Resilience4j Docker Maven Git Fly.io Newrelic Checkstyle Testcontainers Wiremock Mockito JUnit OpenAI API

  • Tick42

    June 2020

    This is when I decided to explore the market in Bulgaria. Luckily, someone recommended Tick42 (now interop.io). I had a couple of interviews with them, and in less than a week, I received a nice offer from them.

    My time at Tick42 was immensely rewarding, surrounded by highly skilled developers and excellent managers. Occasionally, I had the opportunity to lead a small team, and many times I mentored other developers in my area of expertise, which, by this time, was Backend Development with Java and the Spring ecosystem. I had the opportunity to learn directly from the top management and technical leaders and got involved in projects where I had to interact directly with our clients.

    As part of my daily job, I had to design, develop, test, and maintain backend features using Java, running on top of Spring Boot. I also designed and implemented business metrics using Java, Prometheus, and Grafana. As is typical in our profession, I participated in scrum activities and CI/CD processes as part of a multicultural agile team.

    3 Projects Fintech Professional Services

    Java Spring Boot Oracle Liquibase Hibernate Grafana Prometheus.io Maven Gradle Cucumber Cloudfoundry Git Wiremock Mockito JUnit

  • Musala Soft

    April 2019

    By 2018, I was feeling stuck and making little progress in my career path. I decided to look for opportunities abroad, now with 4 years of professional experience under my belt.

    In November of that year, I received an offer from Musala Soft, and by the end of March 2019, I had moved to Bulgaria. I officially started working in April.

    At Musala, I designed, developed, and tested product features using TypeScript/JavaScript and Java. I participated in pair programming with awesome colleagues from whom I learned a lot. I engaged in daily scrum activities, planning, refinement, retrospective sessions, and knowledge-sharing sessions as part of an agile development team.

    Everything was going quite well so far, except for two things: I started to feel like I was doing a "code monkey" job, and I was barely making ends meet (now in a different country/market/cost of living).

    1 Project Fintech

    Java TypeScript JavaScript Angular Spring Boot Hibernate Oracle Maven Git Mockito JUnit

  • ISA - Soluciones en Software

    August 2016

    It wasn't until I started at ISA - Soluciones en Software that I realized how demanding the software industry can be. Throughout my time there, I worked on three products 1 2 3 commercialized mainly in Uruguay and Paraguay.

    My team was located in Havana and worked closely with our colleagues in Montevideo to provide product updates and release. During this time, I designed and developed many of these products' features, using JavaScript, Java, and Groovy and Oracle database.

    3 Projects Professional Services

    Java Groovy Hibernate JavaScript Oracle Gradle SVN Git


    1 : Sistema de Información Policial

    2: MiRecibo

    3: iSCert

  • Got my first job

    June 2014

    Securing my first job at Universidad de las Ciencias Informáticas as a professional software engineer after graduating from university was an exhilarating experience. The opportunity to apply the knowledge gained during my studies in a real-world setting was immensely rewarding. I was filled with excitement and enthusiasm to embark on this new chapter in my career, eager to contribute my skills and learn from seasoned professionals in the field.

    This milestone marked the transition from academia to the professional realm, and I was thrilled to embark on this journey of growth and development in the software engineering industry. There, I had the responsibility of designing, developing, and maintaining two APIs, using Java and PHP, to integrate clients with an in-house developed reports server.

    1 Project Professional Services

    Java PHP XML Apache Tomcat SVN

  • Graduated as Engineer in Computer Science

    June 2014

    I was extremely excited to have received my university diploma from "Universidad de las Ciencias Informáticas", Havana, Cuba. The culmination of 5 years of hard work and dedication resulted in an immense sense of accomplishment and pride. Obtaining this credential marked a significant milestone in my academic journey, representing the knowledge and skills I've acquired throughout my studies.